1. Field of the Invention
One or more embodiments of the present general inventive concept relate to an apparatus and method of encoding or decoding an audio signal, such as a speech signal or a music signal, and more particularly, to an apparatus and method of encoding or decoding a plurality of signals including two or more channel.
2. Description of the Related Art
In AMR-WB+ (Extended Adaptive Multi-Bitrate Wideband), each of a left signal and a right signal is divided into a low-frequency signal and a high-frequency signal through a pre-processing unit/analysis filterbank. In this case, stereo encoding is performed by downmixing the left low-frequency signal and the right low-frequency signal to a mid signal and a side signal. The mid signal is encoded through algebraic code excited linear prediction (ACELP)/transform coded excitation (TCX). The left high-frequency signal and the right high-frequency signal are encoded through bandwidth extension (BWE). The resultant encoded signals are multiplexed into a bitstream and then the bitstream is transmitted to a decoding terminal. The decoding terminal receives the bitstream, and decodes it by performing the above process in a reverse manner.